Make AgentChat Team Config Serializable

[victordibia]

Why are these changes needed?

Support a developer experience where an AgentChat team configuration can be serialized to a declarative specification.

# dump
agent = AssistantAgent(
    name="assistant",
    model_client=model_client,
    handoffs=["flights_refunder", "user"],
    tools=[web_search],
    system_message="Use tools to solve tasks.",
)
team = RoundRobinGroupChat(participants=[agent], ...)
team_spec = team.dump_component() 

TBD

• Agent serialization is currently blocked on Declarative BaseChat Agents #5055 to enable agent serialization. Once done, will update this.
• Update tests

Related issue number

Closes #5064

Checks

• I've included any doc changes needed for https://microsoft.github.io/autogen/. See https://microsoft.github.io/autogen/docs/Contribute#documentation to build and test documentation locally.
• I've added tests (if relevant) corresponding to the changes introduced in this PR.
• I've made sure all auto checks have passed.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 70.80%. Comparing base (58d789a) to head (b598377).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5071      +/-   ##
==========================================
+ Coverage   70.53%   70.80%   +0.27%     
==========================================
  Files         174      174              
  Lines       11129    11229     +100     
==========================================
+ Hits         7850     7951     +101     
+ Misses       3279     3278       -1     

Flag	Coverage Δ
unittests	70.80% <100.00%> (+0.27%)	⬆️

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[victordibia]

Some updates on this effort on here so we can have a broader discussion.

There are a few current issues with making teams declarative (or more generally - elements that inherit from a protocol cannot be declarative in the current setup without mypy/build errors).

The short story is that:

• the inheritance structure for Agents is ChatAgent ->BaseChatAgent -> AssistantAgent.
  • ChatAgent is a protocol .. it cannot be declarative/component as it can only inherit from protocols
  • BaseChatAgent is an abstract class and can be made a component .. so this is where component behaviors for agents begin
• Teams (e,g RoundRobinGroupChat, Selector ...) have a participants arg which is typed as List[ChatAgent]
  • However, when we serialize/deserialize we can only return BaseChatAgent classes
    Mypy/pyright throw errors ... ChatAgent does not have dump_component etc

Similar situation with SocietyofMindAgent. It has a team field that inherits from the Team protocol. While we can serialize base Team classes, mypy still fails as the Team protocol itself cannot cannot inherit from ComponentBase.

Some potential solutions/directions

• update participants type to List[BaseChatAgent] instead of ChatAgent (has its own issues)
• Make ChatAgent an abstract class - not a protocol ...(seems we mix protocol and base class inheritance a few times in agentchat ...)
• Modify Component config design to accomodate Protocol?
• Something else ..

@ekzhu , @jackgerrits

Edit: Resolution -> we are moving to ABC's for components.

[ekzhu]

Just a comment on the name. This work is not to make agent chat declarative -- the agentchat API is already declartive.

It is to make the configuration serializable. So should update the title and fix how we mention it for precise language.